Traditionally, office chairs have been constructed by men for men. Even though over the last decades women are just as common as men in offices, this is to a great extent still true. Most chairs are adaptable to fit persons of different length and different weight, but the main features are still adapted for men. This invention is based on extensive studies of ergonomics as well as physical and social factors, from which it has been determined that there are differences in the way women and men are sitting in office chairs.
In WO2010/087760, an office chair is described in which a lumbar support is activated for supporting the lumbar back portion of a person seated on the chair when said person is leaning forward. This chair offers support for the everyday working position for persons working in an office.
However, it has been desired to develop the office chair in WO 2010/087760 even further, since the design of the lumbar support results in that the force for adjusting the lumbar support has to be increased continuously as the lumbar support is continuously curved from an inactive position to a fully active position. For minimising the resistance given by the padding and fabric in the backrest of the chair when the lumbar support is in motion, it is important to find a material with the appropriate thickness for the padding, and an appropriate fabric for the backrest of the chair, this is costly. To be able to generate forces high enough to overcome the resistance given by the lumbar support, the padding and the fabric in the backrest, when the lumbar support is adjusted from the inactive position to the fully active position, the actuator device will have a complex structure and will hence be expensive.
Thus, there is a need for a chair with a lumbar support that gives as little resistance as possible when adjusted between the inactive position and the fully active position and that is cheaper to manufacture than previously known chairs. The invention is based on this discovery and the inventive chair has been elaborated especially for women but can be made in any size and is not limited to fit persons of a certain size or figure.